You are here

Has Evolution Trained Our Brains to Gorge on Food and Sex?

Can dopamine receptors reveal clues about binging?

A guinea pig called Sooty enjoyed a night of passion with twenty-four females after fooling his way into their cage in south Wales. Sooty wooed the lady guinea pigs, one by one, and has now become the proud father of forty-two baby guinea pigs. . . . "He was absolutely shattered. We put him back in his cage and he slept for two days."

The Coolidge Effect is biology's gallant resolve to leave no novel mate unfertilized whatever the cost. It's typical in mammals, has also been seen in females, and can be traced all the way back to our distant relatives: rodents. Although we humans are pair bonders, our bonding program still competes with this older have-opportunity-will-get-it-on impulse.

All animal behavior, including the Coolidge Effect, is based on the rise and fall of neurochemicals and changes in receptors. Recent research suggests that some of the mechanics behind Sooty's heroic feat may lurk in the striatum—a complex group of structures that function as the central hub of the brain's reward circuitry. The striatum is associated with reward and aversion, and strongly influences our decisions. Sex, love and bonding run through these structures. If they don't light up, "it ain't happening."

For example, recreational drugs often flood the brain with dopamine. Key neurons in the striatum react by shutting down lots of D2 (dopamine) receptors, bringing the high to an end. This mutes feelings of reward and motivation until the brain recovers. Fewer D2 receptors mean, "I need more dopamine to feel okay." The reward circuit is crying our for stimulation and only the really exciting stuff will do. Sex, drugs and rock 'n' roll...or maybe Häagen Dazs. In fact, heavy drug users with depleted dopamine receptors tend to lose interest in sex and bonding; they need stronger kicks.

In the research mentioned above, scientists seeking to learn more about binge eating in humans reported some interesting dopamine-receptor findings. Feeding rats super-stimulating food (fatty cheesecake and sausage) swiftly decreases the number of D2 receptors. Where? In the striatum. After the rats had eaten their last morsel of super-yummy food, receptor density remained low for at least two weeks (the duration of the experiment).

As with recreational drug use, the striatum reacted to the over-stimulation, but it did so very differently from the way it reacts to, say, cocaine. In the case of cocaine, D2 receptor density bounces back in two days (although other changes may continue). But with food—a natural reinforcer (buzz)—the D2 depletion continues far longer. It's curious that the depletion lasts longer after food, considering that cocaine causes a bigger blast of dopamine. Is a genetic program kicking in?

Something more sinister was going on, too. As with continued drug use, the brains of the rats registered less pleasure activation. And it showed up in their post-binge behavior: standard rat chow lost all appeal. Consumption remained lower than normal for weeks. "Cheesecake or nothing," the rats seemed to be thinking. (Interestingly, the opioids produced by sugar consumption act as another anti-satiety mechanism by interfering with oxytocin production.)

Obviously, a "binge trigger" (via whatever mechanisms) is an evolutionary advantage in situations where survival is furthered by engaging in a behavior past the point of normal satiety. Think of bear gorging on high fat salmon before hibernating. Or wolves, which need to stow away up to twenty pounds of a single kill at one go. Or our ancestors, who needed to store high-quality calories as a few extra pounds for easy transport to survive hard times. Or yourself when you're jam-packed with turkey and mashed potatoes and your favorite Thanksgiving pie appears.

When our primitive brain perceives something as really valuable, it wants us to exploit the golden opportunity...fully. It can't do that with warm, fuzzy feelings of satisfaction. Nope. It has to create feelings of lack or dissatisfaction (cravings) in order to drive us past our normal limits.

Key changes in receptors make us feel like something is...not right. We want to feel good again, whatever it takes. Not everything will do it for us, either. We won't settle for normal, because our brains want us to focus on the super-goodies...only. Normal levels of dopamine aren't enough. We become demanding. We want something hyperstimulating, something that registers as "high value" (whether or not it is), something that will trigger release of the dopamine (and pleasure response) our brain is now craving. Dopamine is released when something is better than expected, and a spike of dopamine will stimulate the few remaining receptors in the striatum to give us another taste of good feelings...before we feel dissatisfied again.

Keep in mind that the reward circuitry's job is to remain slightly dissatisfied even under the best of circumstances. In this way, we're primed to seize promising opportunities, or look forward enthusiastically to the deferred gratification of achievement, successful courtship or saving to increase future options.

Normally this aspect of our make-up gives us a zest for life and accomplishment. But when we over-stimulate and desensitize our reward circuitry, normal pleasures and ambitious plans for the future don't offer the usual buzz. Worse yet, we may not value the companionship and warm affection we tribal, pair-bonding primates need for a sense of well-being. Instead, we're likely to feel very dissatisfied—even with our loved ones—and quite certain that any fault lies with them for not meeting our exaggerated needs. We want immediate gratification, even if we imperil our future goals. Our genes have successfully hijacked our attention for their goals.

Could a better understanding of how super-stimulation alters receptor density help humans to make sense of the fact that 65% of Americans are overweight and men with computers everywhere find Internet porn riveting? Are we being pushed around by low D2 receptors and other related brain changes caused by, what would have been for our ancestors, truly extraordinary stimulation?

A gadfly brain signal becomes a risky liability where highly prized foods or extraordinarily stimulating novel mates are available in inexhaustible supply. When the binge trigger remains activated, satisfaction eludes us no matter how much stimulation we consume or experience. Ironically, when someone finds himself seeking hotter and hotter stimuli, it's not because he is getting more pleasure, but because he is getting less. A breath of air is glorious to a drowning woman because her oxygen is low. Similarly, a numbed brain is seeking what it doesn't have—pleasurable stimulation—because its normal sensitivity is reduced. A feverish urge to seek pleasure can easily be mistaken for pleasure, even if it is technically the elusive promise of pleasure.

The rats in the study quickly became obese when offered unlimited amounts of extravagancies. Unlike normal rats, they didn't lay off the goodies even when threatened with electric shocks. They ate to unhealthy extremes; they were not satisfied. Think drug addicts.

Do porn users struggle against this same binge trigger in the striatum when they can't get enough of the highly stimulating new "mates" who beckon at each click? Sooty got a much-needed rest after mating with the cage full of females, but a porn user's work is never done. There's always another virtual "mate" moaning for attention. Our brains goad us to stay on task when goodies abound. There seems to be something unique about our brain's response to very tempting food and sexual stimulation.

It may also be that when orgasm hasn't offered a full range of soothing bonding behaviors (as in sex without a partner), we are especially vulnerable to feeling dissatisfied soon afterward. After all, from our genes' perspective, our fertilization duty isn't done. If so, is this horniness true libido—or synthetic insatiability caused by brain changes that dampen feelings of satisfaction?

Is it possible that even one orgasm sometimes increases subsequent cravings? No one knows for sure. However, a rat's dopamine receptor density declines sharply with its first heavenly helping of fatty food. There seems to be some overlap in the binge trigger that drives both mating and eating. Recovering porn users find that consuming junk food increases cravings for porn during withdrawal. And perhaps you've heard that popular joke about the ideal girlfriend, who turns into a pizza at midnight.

The neurochemistry of orgasm and eating certainly can't be reduced to D2-receptor changes. However, receptor changes could definitely be part of the puzzle of why sexual desire sometimes escalates without offering lasting satisfaction. (If the concept of a lingering cycle after orgasm is new to you, you might be intrigued to learn that research has already revealed a cycle of at least seven days in men.)

Maybe research will one day furnish a roadmap of brain changes after different sexual activities. Then we won't be left solely to the mercy of our brain's binge trigger in our search for contentment.

Explained researcher Paul Kenny, the brain releases dopamine in response to enjoyable experiences such as eating cheesecake, having sex or snorting cocaine. But, too much pleasure skews the brain's reward pathways by overstimulating the D2 receptor and causing it to shut down. For the rats addicted to junk food, the only way to stimulate their pleasure centers was to eat more high-fat, high-calorie food. "They're not experiencing rewards the way they should," Kenny said.

Comments

Can I ask just one thing. so that I can continue to read such articles. the images that have been used in a few of these makes me have to close them. I had to just scroll past the image in the this article to type this. It is impossible for me to read this article with that image there. I do not care if it is just a drawing.

there are other articles that I have had to just close for the same reason. I do not remember the article but it was a recent one or recent update but it had a women kind of face away leaning over. I can picture her just fine from the brief view I had of her and I remember nothing of the article.

I just wanted to thank you. I just stumbled upon your site and found it very helpful to understand what's going on inside me when I crave for food, sex or alcohol. Very looking forward to your book and the insights you share.

[Having been porn and orgasm free for weeks] I have started to notice a shift in my perception of women. I am for once starting to see through the make up that women wear and the purely physical attraction, and am actually starting to get a sense for the, low-and-behold, human being underneath. This could get a little scary. Not that I was previously overly sexist, generally I think I am probably one of the most feminist people I know (due to my own shame) but I sense a whole new world of pain around the corner.

Sometimes it seems like the puberty that I never allowed myself to have.

Today (Saturday) marks the end of my 5th week. Like yourself, I am starting to feel some changes that are so difficult to describe. I am starting to look at women differently myself. I can't explain it, but I am looking at them less lustfully, and I am noticing them more. Somehow more attractive, but in a non-sexual way.

What is shocking me is that the urge to ejaculate is really starting to subside. Sure, the urge still exists, but it is much less strong than after two or three weeks.

I agree with you, I am not so quick to want to set the dial back to zero. I am liking the state I am in.

Well, I had to search a lot to find your book - actually it was mentioned by a well-known danish relationship therapist in one of her articles. Ironically, she promotes the exact opposite of you, such as claiming that the way to happiness is keeping the sexual game up by trying out new things and pleasing the other. She writes a lot of articles about how to make your partner orgasm. Well, I think it is a personal choice. I haven't tried out any method to full potential, but I like not having to perform all the time, because performing breeds failures, failures breed frustration. Mostly, when I see those guides (10 steps to make your partner orgasm, as if it were "how to fix a microwave"), I get the same feeling as from sickening unhealthy food. Funny how things change, as you change your perception.

I responded:

Most all sex therapists counsel "more stimulation" and "more novelty" to bring couples into harmony. However, it looks like the more intensely you stimulate the brain, the less sensitive it is for a time afterward, so obviously it's easy for that strategy to backfire. "Less is more" is a sounder long-term strategy, even though it doesn't appeal to us humans very much. As you say, when you can feel in love without believing that "intense arousal = love," then there's far less resentment when one partner or the other isn't fired up to perform, or their brain is still recovering.

PET imaging shows fewer dopamine receptors in drug addicts
A PET imaging protocol that visualizes the activity of the brain's reward circuitry has been developed and will help in determining what treatment strategies might be most effective in individuals addicted to drugs, according to a presentation at the American Society for Biochemistry and Molecular Biology's annual meeting, a part of the Experimental Biology 2010 conference on Monday April 26 in Anaheim, Calif.

Joanna Fowler, PhD, senior scientist at the U.S. Department of Energy's Brookhaven National Laboratory in Upton N.Y. and her colleague, Gene-Jack Wang, MD, senior scientist at Brookhaven, along with Nora D. Volkow, MD, director of the National Institute on Drug Abuse in Bethesda, Md., combined PET with radioactive tracers that bind to dopamine receptors. The PET scan highlights the movement of the tracers in the brain, and was used to reconstruct real-time 3D images of the dopamine system in action.

The researchers performed PET scans on several drug-addicted volunteers, as well as age-matched healthy control subjects and found that people with addictions in general have 15-20 percent fewer dopamine receptors than normal subjects and thus cannot bind to a lot of the dopamine released in response to the drugs or natural reinforcers like food.

Fowler added that the study looked at multiple recreational drugs and found similar results. "[W]hile various drugs operate by unique mechanisms, they all share a commonality in that the dopamine receptors in the brains of addicted individuals show an under-stimulated reward system."

Wang also used the dopamine PET scans on obese individuals and found highly similar patterns of low dopamine receptors–validating that at least in some cases, obesity can also be considered a disease of addiction. [This means it could easily be used on porn users, too.]

First, I'm a heterosexual male. A few months ago I found out a problem I have, that, whenever I orgasm (ejaculation OR otherwise) I want to kill myself. I feel incredibly down, which I think is somehow related to my two years of clinical depression. My psychiatrist advised that I have a sexual partner, as the oxytocin affects of skin contact etc. will likely somewhat offset the negative feelings, but that's not a solution... I am then at the whim of someone else for any sexual satisfaction or pleasure. (Your posts advise that non-satiating sex can be pleasurable, even better, but can the same be true of non-satiating porn-use or masturbation?? I found masturbation no fun whatsoever till the end, and why would I - no oxytocin).

So, a few months ago I stopped masturbating. I have no sexual partner (due to INCREDIBLE lack of social skills, but, that aside...) and have thus not had an orgasm of any sort for months. And the difference with how I view women and my desire to ejaculate, as well as territorial behaviour and agression to alpha males: None. No difference. Except, I'm hornier, want to ejaculate more (read: NEED RELIEF) and less attractive women look more attractive, and more attractive women look MUCH more attractive. It's killing me...
So it begs the question, did you the OP (and the posters above) come across Karezza information before or after you started trying it? Because, it may just be that the differences you think you are seeing are only there because you're looking for them - sort of like placebo or nocebo.
It may also be that the differences the posters see is not because of change in Dopamine, but change in Oxytocin. Respecting women more if you have a female partner could well be the association of the feminine sex with your partner, and thus, by respecting your partner, you respect women more. Kind of like, once you've picked a favourite sports team, you enjoy the company more of those who support the same team.

I notice no differences whatsoever. (And I wish I did, I wish the craving would stop).
Don't be offended by my comment - I am looking for a solution to my problem, not trying to troll your post, and I believe neuro-chemistry is where the solution may lie. Which is how I found this site.

The information on this site may be true but, like mentioned in the previous post, there seems to be gaps. If drug addict cravings decrease desire for food as it is less satifying than the drug, why does binge-eating help smokers quit - instead of making them want to smoke more? does, in laymans terms, binge-eating make people less horny?

Secondly, why do drug addicts continue using the drug with weakened results?: A coke user needs more and more for the same effect, but, knowing this and with only access to a relatively small amount, would a cocaine user turn it down? See, with regular sex - as sex therapists such as Tracey Cox advise - desire for sex increases and even if your partner is seen as less desireable, if that's all you have available, you'll take it. The craving balances out the lessened desire at extreme levels of sex frequency as well.

---Also, changing environments and outfits (and thus role-play) helps. Dopamine and other chemicals develop associations with the aspects that satiate them, including the environment. If you have sex in different rooms, positions, and with different backround music and lighting with your partner, your cravings for your partner will not be lessened as much. Trust me, but if anyone doesn't believe me, search for the evidence. I was in a long-term sexual relationship and, every time we moved to a new house, my libido (or just my desire for her, I guess) rose.

---Also a story: a while back I developed an addiction to Propofol (the stuff that killed MJ), from regular hospitalisation, but my addiction faded because each time I had access to it (a controlled amount - I could never increase the levels as my dopamine begged - although I admittedly did beg my doctors for more) it was less satisfying. Eventually, euphoric recall became less satisfying as well, and my desire for it sank just as it became less satisfying. Limit drug use, and you can cure the addiction.
Thirdly, Is dopamine the only crave factor in the brain? Surely, then if drug and sex cravings work alike, going cold-turkey should reduce sex cravings, right? Why hasn't it for me??? :(

---Also, I should point out what seemed to be a mistake. In a previous article, it was mentioned that relaxing bonding behaviours and those designed to create sexual tension are different. The key word being Tension. I wish to point out that this is not true - to orgasm, arousal and sexual tension has to constantly increase (this is also needed to maintain an erection, which is why long, slow sex {with men} often ends...ahem...softly). Also, to orgasm, the mind has to be totally relaxed - literally. To orgasm, all stresses and tertiary concerns have to be put out of mind, or other words, the part of the brain (amygdala, was it?) that handles these stresses shuts down. This is also why orgasm temporarily relieves headaches ("No sex tonight, I have a headache!" "That's fine honey, sex will cure it"). Essentially, the more sexual stimulation you get, the more relaxed you are - mentally, not physically, as heart-rate etc. increases...

Fourthly, orgasm in this site with regard to men seems to be associated with ejaculation. What about non-ejaculation orgasms? How is it influenced by the Coolidge Effect? How is it that desire lessens, but not nearly as much, after non-ejaculation orgasms? (Even after non-ejaculation orgasms, I still want to kill myself... I just stay horny as well!).

-I have many more questions and comments for the Admin of this site, some involving dopamine and its association with low-frequency light, but what I have said here I feel is valuable for any readers to see. Please, don't block this comment.

DeanTM
P.S. I have not read all the articles, but am trying hard to - and I doubt, after having read them all, that I could recall all the information.

Oh, and I also read somewhere - don't know if it's true - that the effects of Oxytocin can in some areas counteract the effects of Dopamine... Hence why it lessens addictions, it would also lessen sexual desire. Lots of sex can mean D I V O R C E, I get that, but I LIKE orgasms, and my parents are divorced... so I need extra provocation to try Karezza. And a girlfriend.

A few months ago I found out a problem I have, that, whenever I orgasm (ejaculation OR otherwise) I want to kill myself. I feel incredibly down There’s a large group of mostly men who suffer from what they term POIS. Here’s a link: http://www.reuniting.info/science/post_orgasmic_illness_syndrome . Many us feel different after orgasm, but this group experiences debilitating symptoms.

None. No difference. Except, I'm hornier, want to ejaculate more (read: NEED RELIEF) and less attractive women look more attractive, and more attractive women look MUCH more attractive. I would feel the same, if didn’t have a partner. A lot of the guys here are getting off porn, so they abstain. But the name of this site is Reuniting, rather than “No Orgasm”. It’s about bringing male and female together, practicing karezza . It’s not about solo practice, though many here are practicing solo.

Because, it may just be that the differences you think you are seeing are only there because you're looking for them - sort of like placebo or nocebo Nope. No placebo. Having practiced this for 10 years, that much is clear. Marnia has delved into this for 20 years. And there is a long line or practitioners and literature on “Karezza”, going back thousands of years (under various names). There is much in CPA, and on this site, about the many traditions.

It may also be that the differences the posters see is not because of change in Dopamine, but change in Oxytocin. If you mean – seeing women differently – it may be a change in both neurotransmitters (and a whole lot more). I think getting off porn and reducing masturbation increases dopamine receptors, altering people's outlook in many ways.

The information on this site may be true but, like mentioned in the previous post, there seems to be gaps. If drug addict cravings decrease desire for food as it is less satifying than the drug, why does binge-eating help smokers quit - instead of making them want to smoke more? does, in laymans terms, binge-eating make people less horny?First, this is not an all encompassing site. Secondly, there’s a whole lot more to learn about addiction – science is just scratching the surface.
I think you have answered your own question: The drug reward may replace food reward, or inhibit hunger – it depends on the drug. Similarly, food replaces nicotine. Most addicts replace one addiction with another because they suffer from low dopamine receptors. In addition some addictions are reinforcing (a different mechanism), such as alcohol and nicotine.

Is dopamine the only crave factor in the brain? Surely, then if drug and sex cravings work alike, going cold-turkey should reduce sex cravings, right? Why hasn't it for me??? Dopamine is central to desire, or wanting something. Liking is different and probably based on opioids and cannabanoids. However, many other chemicals are involved in cravings (glutamate, delta-fosB, CREB, etc.). Drugs and sex are not exactly the same (read the above articles). This is an important point. Sex and food are natural reinforcers. Natural reinforcers are what the reward circuit and dopamine evolved to motivate you to pursue – not drugs. So food and sex have unique neurochemical signatures and additional satiation mechanisms. Keep in mind that everyone likes delicious food and the feelings of an orgasm, but only a small percentage of people who use heroin get addicted to it. You are meant to crave sex and food, not drugs. And you do. You started craving sex at puberty. It’s a genetic program. We evolved to crave connecting with another on a sexual level. Again, this site is not called “grit your teeth and don’t come”. It’s a site dedicated to learning to make love a different way, and associated historical/esoteric aspects. ( http://www.reuniting.info/another_way_to_make_love)

Also, I should point out what seemed to be a mistake. In a previous article, it was mentioned that relaxing bonding behaviours and those designed to create sexual tension are different No mistake. This type of lovemaking involves no orgasm. Read the – above article and http://www.reuniting.info/lazy_way_to_stay_in_love.

What about non-ejaculation orgasms? How is it influenced by the Coolidge Effect? We think that under most circumstances they are the same as conventional sex, but others disagree. The issue is degree of stimulation of the brain...not presence or absence of semen.

Oh, and I also read somewhere - don't know if it's true - that the effects of Oxytocin can in some areas counteract the effects of Dopamine... Hence why it lessens addictions, it would also lessen sexual desireIncorrect. Oxytocin and dopamine are synergistic not antagonistic. In sexual activity and reward, oxytocin increases dopamine, and dopamine increases oxytocin. This is surprising to many – even though it is the basis for nearly everything we suggest. For example, to bond or fall in love you have to have both activated; to have an erection- both; to have an orgasm – both. Yes, oxytocin does decrease cravings for drugs, yet the exact mechanisms aren’t understood. Oxytocin does reduce stress response, increase opioids, and activate the reward circuit – all of which could reduce cravings.

Thank you... Some of the links here I can't find on the site in general - such as in the side-bar. How can I access others like them? How much information is on the site???
I appreciate you not taking (too much) offence at my comment. I did not mean to come across as attacking the intentions of this site/project, just as trying to gain a better understanding. Essentially, partnerless, orgasm/no orgasm is a depressing "am I going to get addicted?" or "am I too horny to function?" continuum with no escape. Great :( Do 'They' make meds that repress sexual desire? - that is, as an intentional and limited-side-effect prescription, not a side-effect of other medication such as Dopamine-blockers (How do they lower psychosis???), mood-stabilizers or anti-depressents...
I'd study this all myself, or try, but as a white male in South Africa, that simply isn't a viable option.
I understand that neurological studies are nowhere NEAR completion, or as others put it, in desperate need of a paradigm shift - which is why I'm both skeptical of and interested in anything neurological that overlaps with my studies (on communication, persuasion, and pleasure. And, for fun, sex). As it was famously said, "If the brain was simple enough that we could understand it, we would be too simple to understand it."
I'll contact Admin privately as soon as I've figured out how to... :)

Gary is an administrator. I'm his wife and we are your host and hostess here. I'll let him answer your science questions, as he's the science teacher.

But I just want to say that our premise is that there are longer neurochemical cycles in response to intense stimuli than the mainstream, and even sexologists, have yet acknowledged. This wasn't a big deal for most people when synthetic stimuli weren't as exciting to the brain as they are today, but our environment has changed. We're flooded with hyperstimuli...yet we're still stuck with our ancestors' vulnerable brains.

We think science is on the verge of "getting it," that the issue isn't type of stimulation, but rather degree of stimulation. This means that Playboy magazine didn't produce much dopamine dysregulation, but unlimited Internet porn, with its endless variety and escalation, is apparently quite a different matter in terms of its potential to dysregulate dopamine (and possibly other neurochemicals).

Dear Marnia,
I've read with interest your article about how sensitivity of the reward circuitry is changed over extensive stimulation of food and sex. It is compatible with what is known about psychostimulants and the notion that chronic psychostimulants show reduced sensitivity to drugs and natural reward like computer games that we have shown. It would be extremely interesting to see how sensitivity returns to normal after recovery from drug and behavioral addictions using brain imaging technology.
I have 3 other papers in that special issue of behavioral addictions including the introduction, internet addiction and compulsive shopping that I can send you if you are interested.
Yours sincerely

So there's hope that researchers will start looking at this issue of how long it takes brains to bounce back after too much stimulation.

Meanwhile, my thought is that you may not have to fight your libido forever, if you can just stay away from extreme stimuli. For now, though, you need to emphasize things that make you feel good without sending you on another neurochemical joyride. There are some ideas here, many of which research has already confirmed as helpful to brain balance: http://www.reuniting.info/node/4501 You can probably come up with your own, too.